Antigen-Specific Binding of Multivalent Soluble Antigen Arrays Induces Receptor Clustering and Impedes B Cell Receptor Mediated Signaling
Antigen-Specific Binding of Multivalent Soluble Antigen Arrays Induces Receptor Clustering and Impedes B Cell Receptor Mediated Signaling
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DOI：
10.1021/acs.biomac.5b01097
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发表时间：
2016-03-01
影响因子：
6.2
通讯作者：
Berkland, Cory
中科院分区：
文献类型：
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作者：
Hartwell, Brittany L.;Martinez-Becerra, Francisco J.;Berkland, Cory
存在着对自身免疫性疾病疗法的迫切需求，这种疗法以抗原特异性的方式发挥作用，同时避免全球免疫抑制。多价可溶性抗原阵列(SAGA(PLP：LABL))旨在诱导对特定多发性硬化症自身抗原的耐受，由柔性透明质酸(HA)聚合物骨架与多拷贝自身抗原肽(PLP)和细胞黏附抑制肽(LABL)共移植组成。以前的体内研究表明，两种信号在HA上的共同表达对于治疗效果是必要的。为了阐明治疗细胞机制，在模型B细胞系统中进行了体外研究，以评估结合和特异性。与仅含有接枝PLP或LABL的HA和HA阵列相比，同时显示PLP和LABL的SAGA(PLP：LABL)显示出显著增强的B细胞结合。此外，SAGA(PLP：LABL)的结合亲和力主要由PLP抗原驱动，通过流式细胞仪竞争解离研究确定。荧光显微镜显示SAGA(PLP：LABL)诱导成熟受体聚集的速度比其他只有一种类型接枝肽的HA阵列更快。通过钙通量分析，SAGA(PLP：LABL)分子也减少和抑制了IgM刺激的信号转导。在B细胞中观察到的抗原特异性结合增强、成熟受体聚集和信号抑制的分子机制可能有助于SAGA(PLP：LABL)的治疗效果。
A pressing need exists for autoimmune disease therapies that act in an antigen-specific manner while avoiding global immunosuppression. Multivalent soluble antigen arrays (SAgA(PLP:LABL)), designed to induce tolerance to a specific multiple sclerosis autoantigen, consist of a flexible hyaluronic acid (HA) polymer backbone cografted with multiple copies of autoantigen peptide (PLP) and cell adhesion inhibitor peptide (LABL). Previous in vivo studies revealed copresentation of both signals on HA was necessary for therapeutic efficacy. To elucidate therapeutic cellular mechanisms, in vitro studies were performed in a model B cell system to evaluate binding and specificity. Compared to HA and HA arrays containing only grafted PLP or LABL, SAgA(PLP:LABL) displaying both PLP and LABL exhibited greatly enhanced B cell binding. Furthermore, the binding avidity of SAgA(PLP:LABL) was primarily driven by the PLP antigen, determined via flow cytometry competitive dissociation studies. Fluorescence microscopy showed SAgA(PLP:LABL) induced mature receptor clustering that was faster than other HA arrays with only one type of grafted peptide. SAgA(PLP:LABL) molecules also reduced and inhibited IgM-stimulated signaling as discerned by a calcium flux assay. The molecular mechanisms of enhanced antigen-specific binding, mature receptor clustering, and dampened signaling observed in B cells may contribute to SAgA(PLP:LABL) therapeutic efficacy.